Communication system



Oct. 19, 1943. w. H. SCHEER COMMUNICATION SYSTEM Filed July 17 1941 m I l k\\ m S v 4 m h /NIVENTOR W H. SCHEER WWW Arrows/5v Patented Oct. 19, 1943 COMMUNICATION SYSTEM William H. Scheer, Montclair, N. J assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application July 17, 1941, Serial No. 402,735

2 Claims. (01. 179-85) This invention relates to communication systems and particularly to measured service for party lines. 7

The objects of the invention are to minimize the amount of equipment necessary for the selective operation of message registers; to enable the selective operation of a plurality of registers over a single control conductor; to safeguard against false operation; and in other respects to simplify and improve systems of this character.

In automatic telephone systems having twoparty lines arranged for message register service it is particularly desirable to control the operation of both party registers over a single control conductor extending through the contact bank of the automatic switch in which the line appears. And it is also essential that the selection and operation of each register shall be performed Without causing the false operation of the associated register.

In accordance with the present invention,

these requirements are realized and the foregoing objects are attained by means of a system in which a simple three-element discharge tube is provided for each station on the party line. These tubes are so constructed that the anodecathode gaps are strongly unidirectional, making it possible to obtain the selective operation of the tubes by connecting their electrodes to the single control conductor. More specifically, the unidirectional main discharge gap of one tube is connected in series with the control conductor and the associated register in a direction to transmit current of one polarity, whereas the main discharge gap of the other tube is connected in series with the control conductor and the other register in a direction to transmit current of the opposite polarity. The control or starting gaps of both tubes are also connected in series with the control conductor and the associated message registers. Thus the application of operating voltage of either polarity to the single control conductor causes both starting gaps to ionize, but only one of the tubes transmits operating current through its discharge gap to selectively operate the desired register.

Other features and advantages of the invention will be explained more fully in the following detailed specification.

The drawing accompanying the specification illustrates a portion of an automatic telephone system incorporating the features of the present invention.

Although the invention is applicable in its broader aspects to the selective control and operation of registers or similar devices when used in various types of system, such as telephone, telegraph or other communication systems, it has been disclosed herein for the purpose of illustration in a two-party message register telephone system of the automatic type.

Referring to the drawing, the subscribers line I00, having two substations IUI and I02 thereon, appears in the terminal bank of an automatic switch, such as a line finder switch F. The finder F is joined by a link or trunk circuit I03 to a first selector switch S, which, together with succeeding switches, serves to extend the line I03, when calling in the direction of a called line.

The line Ill!) is provided with the usual line and cut-off relays I04 and I05 and with message registers I06 and I I3! and space discharge tubes I08 and IE9. tube I08 are individual to the party station IOI, and the register I01 and tube I09 are individual to the other station I02. The tubes I08 and I09 are of the type having three separate electrodes, an anode, a cathode and a starting electrode. The anode and cathode form the main discharge gap, and these electrodes have different shapes so as to give the gap a strong directional characteristic. The starting electrode and the cathode form the starting gap, and since these electrodes are similarly shaped, this gap is non-directional in character. Although both gaps present a high impedance when deionized, the starting gap ionizes on a much lower voltage than the main gap. The three electrodes are enclosed in acontainer filled with any suitable gas or mixture of gases. Two of the electrodes, the cathode and the control or starting electrode, form a control or .ionizing gap for starting purposes; and the third electrode, the anode, forms the main discharge gap with the cathode. The control gap is non-directional, that is, it ionizes when potential of either polarity and of sufficient magnitude is applied thereto. The main discharge gap, however, is highly directional; it will conduct current of one polarity in response to the ionization of the control gap, but it will pass very little current of the opposite polarity. The meters I06 or It! shall be constructed to operate on the high current flow and not to operate on the low current flow. V

In the present system the unidirectional character of the main discharge gaps of the tubes serves to enable the selective operation of the registers over the single control conductor IIO. To this end the anode I II and the control electrode II2 of the tube I08 are connected to the The register I06 and the associated conductor IIO, and the cathode H3 is connected through the winding of the non-polarized message register I06 to ground. The other tube I09 has its cathode I I4 connected to the control conductor H and its anode H5 and control electrode II6 connected through the winding of the register I01 to ground. By analyzing these electrode connections it will be seen that if positive potential is applied to the conductor II? when the control gaps of both tubes are ionized current will flow across the main discharge gap of tube I08 from anode II I to cathode H3 and through resistor I06, whereas current in any substantial amount will not flow across the main discharge gap of tube I09. On the other hand, if ne ative potential is applied to the control conductor IIII while both control gaps are ionized, current will flow through the main gap of tube I09, operating register I01, whereas no appreciable current will flow through the other tube.

The link I03 interconnecting the finder F and first selector S is provided with'the usual controlling equipment for controlling the switches, for making the party line test to determine which station is calling, and for applying voltage ofthe proper polarity to the control conductor for operating the register corresponding to the calling line. Much of the equipment has been omitted in the drawing for the sake of clearness. It will be understood, however, that the automatic switches, the link controlling equipment and the circuits at the substations IOI and I02 may be of any suitable types such as those disclosed in the patent to Johnson et al. 1,804,778, of May I2 1931.

To further explain the operation of this 5 tem it will be assumed that the subscriber at sta tion I0! wishes to make a call. When the calling party removes his receiver, the line relay I04 operates in an obvious circuit and applies ground potential to the start conductor II1 to start the movement of the line finder F. When the finder F advances its brushes to the terminal of the calling line I00, a circuit is closed from batter through the winding of cut-oil relay I05, contacts of line relay I04, sleeve conductor I I8 through the terminal and brush of the line finder F to ground over conductor I I9. The cut-off re.- lay [05 operates and locks in this circuit, and the line finder F comes to rest. The operation of cu t-oil relay I05 releases the line relay I04.

Thereafter-the subscriber manipulates his dial I20, to operate the switch S and succeeding switches to establish the desired connection. Also at any desirable time, either while the dial; ing operations are in progress or after they have been completed, a test is made to determine which party is calling. To perform this test the relay I 2I is operated to establish a circuit from battery, through the winding of test relay I22, contacts of relay I2I and thence over both corrductors of the link I03 and line I00 to the calling substation IDI. At this particular substation the test circuit finds a path through the windings of the ringer I23 to ground, Relay I22 in operating looks through its own contacts to grounded con# trol conductor. 7 7

If the calling party is successiul in, establishing the desired connection and the called party answers, the following circuit is established at any suitable time thereafter: ground over conductor I24, front contacts or the operated test relay I, 2 2 through the winding of relay I25 to battery. Relay I25 operates, and 'a circuit is completed-from the positive pole of battery I26, resistance lamp I21, front contacts of relay I25, back contacts of relay I28, conductor I29, brush and terminal of finder F, conductor Hi] to the anode III and through the resistor I3il to the control electrode II2 of the tube I08. This potential is also applied over conductor H0 to the cathode H4 of the tube I98. Since the negative pole of battery I25 is connected through the register I06 to the athode of tu .8 and th aueli h register I01 and resistor I3I to the control electrodes H5 of tube I09, the control gaps of both tubes ionize. These control gaps ionize on voltage, and substantially no current flows through the registers I and I01 sh' ce resistances I30 and I3I are of a high value. The positive pole of battery I26 being applied to the anode III of the tube I08, the ionization of the control gap transfers to the anode, and discharge current now flows over the conductor IIG across the main discharge gap from anode Hi to cathode II3 and through the register I 06 to ground. This current is of sufficient magnitude to operate the register. Since, however, the main gap of the tube I09 conducts in the opposite direction, no substantial amount of current flows through this gap and register I01; hence the register I01 does not operate at this time.

At the termination of the conversation between the subscriber at station ifli and the subscriber at the called station, the connection is released and the circuits are restored to their normal condition.

When the party at station I82 makes a call, the party line'test relay I22 fails to operate since the condenser I32 is interposed between the tip and ring conductors of the line and the grounded terminal of the ringer I 33. Later, when ground is connected to conductor I24, relay I28 operates in a circuit extending through the back contact of test relay I22, and relay I25 remains deenergized. The negative pole of battery I34 is now connected to the control conductor II'O over a circuit traceable through the resistance lamp I35, normal contacts oi relay I25, f ront contacts of relay I28,

' conductor I29 and the brush and terminal of the in nd Sinc the cqntr p o t e es are unidirectional, both of these gaps ionize in resp n e to p li atiq h ret o n v i ln th n e he main. ap. f he ube 9 i har n, a. c rc i a ea le. rom the positive or grounded pole of battery I34 through the winding of register I01, anode U5, cathode. II I, conductor I), and thence as traced to the negative pole of the battery [3,4, The reg;

' ister I01. operates in this, circuit, but, register I05 does not operate.

What is claimed is:

1,. I a ommu ic tion s m. a. e r fice, a line terminating in said central, oliice and hav-. ing two stations. thereon, a pair of messagev reg; isters individual to. said stations. respectively and. located in the. central otlice, a control, conductor r i line, a pa r of d s har e be i d idu es e y to. said s at o s a t ah Qa e n. the central orifice, each, of said tubes having a a e. d a ode ich are sha ed. a pj a unidirectional main discharge. gap, and; a start ing electrode which is shaped tojform; with said cathode a, non-directional starting, gap, circuit means for connecting the. starting gap. o f each tubein series-with id control. conductor, andthe associated register, circuit means for connecting he ma n i c a e p o n i d, ubes in r e w th. a d. Q ll lQl, conduc r. and; h a sociated register to permit the flow of current over said conductor in one direction only, circuit means for connecting the main discharge gap of the other tube in series with said control conductor and the associated register to permit the flow of current over said control conductor in the opposite direction only, said starting and main discharge gaps having high impedances which serve normally to isolate said registers from the control conductor, sources of operating voltage of opposite polarities, means for connecting either one of said sources of voltage to said control conductor to cause the ionization of the starting gaps of both of said tubes, the starting gap ionization of the tube corresponding to the desired register transferring to the anode to cause the discharge of the main gap and the flow of operating current over said control conductor through the winding of said desired register to selectively operate it, and high resistance elements connected in circuit respectively with said starting gaps to prevent the flow of current in the associated registers by Way of the ionized starting gaps.

2. In a communication system, a central ofiice, a party line terminating in said central office and having two substations thereon, a pair of message registers individual to said substations respectively and located in the central ofiice, a control conductor for said line separate from the talking conductors thereof, a pair of discharge tubes individual respectively to said substations and also located in the central office, each of said tubes having a cathode and an anode of different shapes forming a unidirectional main discharge gap and a starting electrode similar in shape to said cathode and forming therewith a non-directional starting gap, circuit means for connecting the starting gap of each tube in series with said control conductor and the associated register, circuit means for connecting the main discharge gap of the first one of said tubes in series with said control conductor and the associated register and in parallel with the starting gap of said first tube, the main discharge gap of said first tube serving to permit the flow of register operating current over said control conductor in one direction only, circuit means for connecting the main discharge gap of the second tube in series with said control conductor and the associated register and in parallel with the starting gap of said second tube, the main discharge gap of said second tube serving to permit the flow of register operating current over said control conductor in the opposite direction only, said starting and main discharge gaps having high impedances which serve normally to isolate said registers from the control conductor, sources of operating voltage of positive and negative polarities, selective means for connecting either the positive or negative source of voltage to said control conductor to cause the simultaneous ionization of the starting gaps of both of said tubes, the starting gap ionization of the tube corresponding to the desired register transferring to the anode to cause the discharge of the main gap and the flow of operating current over said control conductor through the winding of said desired register to selectively operate it, and high resistance elements connected in circuit respectively with said starting gaps and the message registers to prevent the flow of current in said registers in response to the ionization of said starting gaps.

WILLIAM H. SCHEER. 

